Boosting devices, such as turbochargers, are used in engines to provide increased engine output and efficiency. However, it may be desirable to adjust the boost provided to engines based on operating conditions in the engine to improve combustion efficiency and increase power output. To enable boost adjustment, devices such as wastegates are provided to vary the amount of exhaust gas flowing through the turbine rotor, thereby adjusting the speed of the turbine and therefore the speed of the compressor in the turbocharger. As a result, the amount of boost provided to the engine can be varied based on engine operating conditions to provide increased engine efficiency and/or engine output.
However, wastegate operation may interfere with the outflow of the turbine causing backpressure build up, thereby decreasing turbine performance. As a result, turbocharger operation is negatively affected. U.S. Pat. No. 4,256,285 discloses a wastegate valve with a wing member coupled thereto. The wing member interacts with the wastegate flow to assist in valve opening during valve actuation. However, the wing member does not mitigate flow interference between the wastegate outflow and the turbine rotor outflow. Consequently, wastegate and rotor outflow mixing creates a restriction downstream of the rotor, increasing backpressure in the turbine. Therefore, turbocharger performance is negatively impacted by the wastegate disclosed in U.S. Pat. No. 4,256,285. In other prior art turbines flow diverting walls may be integrally formed with a wastegate conduit outlet to reduce flow interference between the turbine outflow and the wastegate outflow.
As such in one approach, a wastegate assembly in a turbine of an internal combustion engine is provided. The wastegate assembly includes a wastegate conduit bypassing a turbine rotor, a valve sealing plate configured to seat and seal on a wastegate conduit outlet in a closed position, and a flow diverting tab coupled to the valve sealing plate, extending upstream of the wastegate conduit outlet, and separating a wastegate conduit outflow and a turbine rotor outflow. The flow diverting tab decreases flow interference between the wastegate outflow and the turbine rotor outflow, thereby decreasing turbine backpressure and improving turbine operation. As a result, turbine efficiency and longevity is increased.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Additionally, the above issues have been recognized by the inventors herein, and are not admitted to be known.
FIGS. 2-4 are drawn approximately to scale, although other relative dimensions may be used.